1. Field of the Invention
The present invention relates to a display device such as a liquid crystal display device, and particularly relates to a display device which includes a capacitance type touch sensor and into which information can be input with a touch by a user's finger or the like, and to an electronic unit having such a display device.
2. Description of the Related Art
In recent years, attention has been given to a display unit in which a contact detection device (hereinafter, referred to as a touch sensor) generally called a touch panel is directly mounted on a liquid crystal display device and causes the liquid crystal display device to display various buttons for input of information in stead of providing typical buttons. Amid a trend towards an increase in the size of a screen on a mobile device, this technique enables an arrangement common to a display and buttons, bringing about great advantages such as space savings and a reduction in the number of components. However, this technique has such a problem that the thickness of the entire liquid crystal module is increased because the touch sensor is mounted. In particular, when this technique is applied to a mobile device, it is necessary to provide a protection layer so as to prevent scratches on the touch panel and therefore, there is such a problem that the thickness of the liquid crystal module tends to be larger, going against a trend towards a reduction in thickness.
Japanese Unexamined Patent Application Publication No. 2008-9750 and U.S. Pat. No. 6,057,903 each propose a liquid crystal display element with a capacitance type touch panel, whose thickness is reduced. In this type, a conductive film for the touch panel is provided between a substrate on an observation side of the liquid crystal display element and a polarizing plate for observation arranged on an outer surface of the substrate on the observation side, and the capacitance type touch panel is formed between the conductive film for the touch panel and an outer surface of a polarizing plate so that this outer surface of the polarizing plate is used as a touch face.